The God Machine (a.k.a. The Colossus) was a device of Atlantean technology built by Nur-Ab-Sal and designed by the horned beings who once brought orichalcum to Atlantis to transform people into supreme beings. However, if the incorrect amount of orichalcum was used, the machine mutated them into deformed creatures.
The God Machine was located in the inner circle of Atlantis inside a massive volcanic chamber. The outer walls held a maze of archways and several statue heads from which lava flowed into the central magma pool. It also featured a dangerous lava moat with cooled lava rocks on top of it which had to be crossed in order to reach the staircase leading to the God Machine.
The machine itself was inside a massive tower that was suspended from the ceiling high above in the very center of Atlantis. The tower was full of lights and machinery and had bridges connecting it to the walls, allowing people to work their way down and reach the machine from the middle circle.